Rotating electric machine

Abstract

A rotating electric machine including a rotator including a small-angle rotator portion and a large-angle rotator portion respectively having different inter-magnet end angles, each being a plane angle formed between a line connecting one outermost peripheral-side end of a permanent magnet and an axial center of the rotator and a line connecting an outermost peripheral-side end of another permanent magnet and the axial center of the rotator. The rotator includes three layers of the small-angle rotator portion, the large-angle rotator portion, and the small-angle rotator portion, which are laminated in the stated order along an axial line of the rotator. Therefore, demagnetization due to a temperature rise of the permanent magnets is suppressed. In addition, a temperature distribution in the permanent magnets in the axial direction of the rotator is reduced.

The invention claimed is: 
     
       1. A rotating electric machine, comprising:
 a stator comprising:
 a stator core having a slot formed by teeth formed at intervals in a circumferential direction of the stator core so as to extend radially inward from a core back having an annular shape; and 
 a stator coil wound around the slot; and 
 
 a rotator arranged coaxially with the stator core on an inner peripheral side of the stator so as to be rotatable, 
 the rotator comprising:
 a rotator core; and 
 a plurality of permanent magnet groups each including at least two permanent magnets having a rectangular shape for one pole, the plurality of permanent magnet groups being embedded in an outer peripheral portion of the rotator core at intervals in a circumferential direction of the rotator, or a plurality of permanent magnets each including one permanent magnet having a rectangular shape for one pole being embedded in an outer peripheral portion of the rotator core at intervals in a circumferential direction of the rotator, 
 
 when the rotator comprises the plurality of permanent magnet groups: 
 each of the plurality of permanent magnet groups is arranged symmetrically with respect to a center of the corresponding pole in the circumferential direction of the rotator; 
 the rotator includes a laminate of a plurality of rotator portions respectively having different inter-magnet end angles, each being a plane angle formed between a line that connects an outermost peripheral-side end of one of the at least two permanent magnets and an axial center of the rotator and a line that connects an outermost peripheral-side end of another of the at least two permanent magnets, and one of the plurality of rotator portions having the larger inter-magnet end angle is arranged at a position closer to a central portion of the rotator in an axial line of the rotator, 
 when the rotor comprises the plurality of permanent magnets: 
 each of the plurality of permanent magnets is arranged such that a perpendicular bisector of the permanent magnet passes through the axial center of the rotator; 
 the rotator includes a laminate of a plurality of rotator portions respectively having different inter-magnet end angles, each being a plane angle formed between a line that connects one outermost peripheral-side end of the permanent magnet and the axial center of the rotator and a line that connects the other outermost peripheral-side end of the permanent magnet and the axial center of the rotator, and one of the plurality of rotator portions having the larger inter-magnet end angle is arranged at a position closer to a central portion of the rotator in an axial line of the rotator, 
 when the rotator comprises the plurality of permanent magnet groups or the plurality of permanent magnets: 
 the plurality of rotator portions include two kinds of rotator portions corresponding to a large-angle rotator portion and a small-angle rotator portion having the inter-magnet end angle smaller than the inter-magnet end angle of the large-angle rotator portion, the two kinds of rotator portions being laminated in order of the small-angle rotator portion, the large-angle rotator portion, and the small-angle rotator portion along the axial line of the rotator; and 
 when a value of the inter-magnet end angle at which a cogging torque becomes the smallest is θ, a value of the inter-magnet end angle of the small-angle rotator portion is smaller than θ and a value of the inter-magnet end angle of the large-angle rotator portion is larger than θ. 
 
     
     
       2. A rotating electric machine according to  claim 1 , wherein the plurality of rotator portions further include a medium-angle rotator portion having a magnitude of the inter-magnet end angle that lies between the inter-magnet end angle of the large-angle rotator portion and the inter-magnet end angle of the small-angle rotator portion, the plurality of rotator portions being laminated in order of the small-angle rotator portion, the medium-angle rotator portion, the large-angle rotator portion, the medium-angle rotator portion and the small-angle rotator portion along the axial line of the rotator. 
     
     
       3. A rotating electric machine according to  claim 1 , wherein when the rotator comprises the plurality of permanent magnet groups, each of the plurality of permanent magnet groups is arranged in a V-like pattern and includes two permanent magnets. 
     
     
       4. A rotating electric machine according to  claim 1 , wherein when the rotator comprises the plurality of permanent magnet groups, each of the plurality of permanent magnet groups is arranged in a U-like pattern and includes three permanent magnets. 
     
     
       5. A rotating electric machine according to  claim 1 , wherein the rotator core includes magnet accommodating holes for accommodating the at least one permanent magnet therein, each of the magnet accommodating holes having gap portions on both sides of each of the at least one permanent magnet. 
     
     
       6. A rotating electric machine, comprising:
 a stator comprising:
 a stator core having a slot formed by teeth formed at intervals in a circumferential direction of the stator core so as to extend radially inward from a core back having an annular shape; and 
 a stator coil wound around the slot; and 
 
 a rotator arranged coaxially with the stator core on an inner peripheral side of the stator so as to be rotatable, 
 the rotator comprising:
 a rotator core including a ventilation path passing therethrough in an axial direction of the rotator; and 
 a plurality of permanent magnet groups each including at least two permanent magnets having a rectangular shape for one pole, the plurality of permanent magnet groups being embedded in an outer peripheral portion of the rotator core at intervals in the circumferential direction of the rotator, or a plurality of permanent magnets each including one permanent magnet having a rectangular shape for one pole being embedded in an outer peripheral portion of the rotator core at intervals in a circumferential direction of the rotator, 
 
 when the rotator comprises the plurality of permanent magnet groups: 
 each of the plurality of permanent magnet groups is arranged symmetrically with respect to a center of the corresponding pole in the circumferential direction of the rotator; 
 the rotator includes a laminate of a plurality of rotator portions respectively having different inter-magnet end angles, each being a plane angle formed between a line that connects an outermost peripheral-side end of one of the at least two permanent magnets and an axial center of the rotator and a line that connects an outermost peripheral-side end of another of the at least two permanent magnets, and one of the plurality of rotator portions having the inter-magnet end angle is arranged on a downstream side of the ventilation path, which is larger than the inter-magnet end angle of another of the plurality of rotator portions arranged on an upstream side of the ventilation path, 
 when the rotator comprises the plurality of permanent magnets: 
 each of the plurality of permanent magnets is arranged such that a perpendicular bisector of the permanent magnet passes through the axial center of the rotator; 
 the rotator includes a laminate of a plurality of rotator portions respectively having different inter-magnet end angles, each being a plane angle formed between a line that connects one outermost peripheral-side end of the permanent magnet and the axial center of the rotator and a line that connects the other outermost peripheral-side end of the permanent magnet and the axial center of the rotator, and one of the plurality of rotator portions having the inter-magnet end angle is arranged on a downstream side of the ventilation path, which is larger than the inter-magnet end angle of another of the plurality of rotator portions arranged on an upstream side of the ventilation path, 
 when the rotator comprises the plurality of permanent magnet groups or the plurality of permanent magnets: 
 the plurality of rotator portions include two kinds of rotator portions corresponding to a large-angle rotator portion and a small-angle rotator portion having the inter-magnet end angle smaller than the inter-magnet end angle of the large-angle rotator portion, the two kinds of rotator portions being laminated in order of the small-angle rotator portion, the large-angle rotator portion, and the small-angle rotator portion along the axial line of the rotator; and 
 when a value of the inter-magnet end angle at which a cogging torque becomes the smallest is θ, a value of the inter-magnet end angle of the small-angle rotator portion is smaller than θ and a value of the inter-magnet end angle of the large-angle rotator portion is larger than θ. 
 
     
     
       7. A rotating electric machine according to  claim 6 , wherein when the rotator comprises the plurality of permanent magnet groups, each of the plurality of permanent magnet groups is arranged in a V-like pattern and includes two permanent magnets. 
     
     
       8. A rotating electric machine according to  claim 6 , wherein when the rotator comprises the plurality of permanent magnet groups, each of the plurality of permanent magnet groups is arranged in a U-like pattern and includes three permanent magnets. 
     
     
       9. A rotating electric machine according to  claim 6 , wherein the rotator core includes magnet accommodating holes for accommodating the at least one permanent magnet therein, each of the magnet accommodating holes having gap portions on both sides of each of the at least one permanent magnet.